Internetworking and the integration of various radio access networks is a general trend within the field of radio communications networks in order to improve the service e.g. regarding coverage and capacity. A general desire is to find efficient means and methods making various radio access networks more compatible, allowing a smooth integration of the physical networks as well as the services. A general problem is thus to find efficient means and methods allowing a smooth integration of various radio access networks. Furthermore, there is a need to find efficient means and methods providing a possibility for smooth handover schemes, efficient interference suppression and access control schemes, in such integrated networks. Important problems relate to how to handle/improve radio link quality control, decrease signaling, packet delay etc. in an efficient way for such integrated networks. Thus, it is a general problem to find efficient means and methods improving the network access characteristics and handover characteristics of such integrated networks.
FIG. 1 illustrates the basic architecture of a cellular radio network, i.e. a first radio access network, in form of a UTRAN (Universal Terrestrial Radio Access Network) network, connected to the Internet 170 and a wireless data network, i.e. a second radio access network, in form of a WLAN (Wireless Local Area Network). The WLAN normally comprises at least one radio Access Point, AP, 165 connected to an Access Point Controller, APC, 162. The cellular radio network comprises a GGSN 110 connected to a SGSN 120 which in turn is connected to a RNC 130. A dual mode UT (User Terminal) 140, having both UTRAN and WLAN capability, can establish a UTRAN radio connection through it's first data port 141 with Base station Node B 150 and a WLAN radio connection through it's second data port 142 with the AP 165 of the WLAN. Node B 150 is connected to RNC 130.
The UT's 140 authorization to access the UTRAN network is in a conventional manner investigated by a 3GPP Authorization, Authentication and Accounting entity AAA1, 1310, before the UT 140 can establish a communication session through the UTRAN network. The AAA1 1310 communicates in a conventional manner with a HLR (Home Location Register) and a VLR (Visiting Local Register), not illustrated in FIG. 1, in order to establish whether UT 140 is authorized to access the UTRAN network. The AAA1 1310 may reside in one of the UMTS core network nodes, e.g. in the SGSN 120, or may reside in a stand alone AAA1 server, 1310, connected e.g. with the SGSN 120, as illustrated in FIG. 1.
The UT's 140 authorization to access the WLAN network is similarly, in a conventional manner, investigated by a WLAN Authorization, Authentication and Accounting entity, AAA2, installed in server a 1630, e.g. an AAA-server, before the UT 140 can establish a communication session through the WLAN network. The APC 162 communicates for this purpose in a conventional manner with the AAA2 at server 1630, e.g. being a RADIUS (Remote Authentication Dial-In User Service) or a DIAMETER server, as illustrated in FIG. 1. Alternatively, AAA2 may e.g. reside in the APC node 162.
The WLAN may in a conventional manner be connected to the SGSN 120 or to the GGSN 110 or to the Internet 170, FIG. 1 illustrates the case wherein it is connected to the GGSN 110, possibly via an AR (Access Router) and/or an IP-network, not illustrated in FIG. 1. A data communication session can be established between the UT 140 and a communicating party connected to the Internet 170, e.g. by means of a conventional PDP (Packet Data Protocol) context session between the UT 140 and the GGSN 110, in accordance with the 3GPP standard for packet radio data services, or by means of a conventional data session through the WLAN, after establishing that the UT 140 is authorised to access the UTRAN/WLAN network.
A problem associated with the network architecture depicted in FIG. 1 is that there is no efficient control of the radio resources of the entire integrated UTRAN-WLAN network, or traffic load balancing between the UTRAN network and the WLAN network, but instead the radio resources are managed separately on a local network basis, i.e. the RNC 130 manages and controls the radio resources of the UTRAN network and the APC 162 and/or the APs manages and controls the radio resources of the WLAN network, which constitutes a problem for obtaining an efficient exploitation of the entire UTRAN-WLAN integrated network.
More specifically, it is a problem how to obtain a cost efficient physical control of a UT's (140) access to the particular sub-networks, i.e. the WLAN and the UTRAN.